The MRI device obtains a magnetic resonance image (tomographic image) representing physical characteristics of a target body placed in an imaging space using the nuclear magnetic resonance phenomenon of nucleus. Generally, the MRI device includes a static magnetic field generating device having a static magnetic field generating source for generating a homogeneous magnetic field (static magnetic field) in a photographing space, a radiation coil for generating a high frequency electromagnetic waves for generating magnetic nuclear resonance in atomic nucleuses of biotissue of the target body, a receiving coil for detecting the nuclear magnetic resonance signal generated by the magnetic nuclear resonance, a gradient magnetic field generating device having a gradient magnetic field generating source for generating a gradient magnetic field having linear variation which is superimposed on the homogeneous magnetic field to provide positional information to the nuclear magnetic response signal. In photographing with the MRI device, the gradient magnetic field generating device magnetically excites nuclear spins at the Larmor frequency in the target body as a result of superimposing the linear gradient magnetic field in the X, Y, and Z axis directions in the target body placed in the homogenous magnetic field according to a desired pulse sequence. In accordance with the excitation, a magnetic resonance signal can be detected, and a magnetic resonance image of the target body, for example, a two-dimensional tomographic image is reconstructed.
In the gradient magnetic generating device and the static magnetic generating device vibrations may occur. The vibrations generated in these devices may be supposed to be a cause for deterioration of the tomographic image and sound noises around the MRI devices. There is a proposed prior art regarding a vibration suppressing method of the MRI device in which a magnetic field leaked from a gradient magnetic field generating source to a side of the static magnetic field generating device is shielded by installing an electric conductor plate which encloses the gradient magnetic field generating device. This reduces eddy currents and Lorentz forces generated in the static magnetic field generating device (see, for example, Patent DOCUMENT 1) to reduce sound noise of the static magnetic field generating device. In addition, there is proposed a technology in which high frequency components in the gradient magnetic field are completely shielded by hard connecting an electric conductor, having a cylindrical shape, surrounding the gradient magnetic field to the gradient magnetic field generating device to reduce the vibrations of the static magnetic field of the static magnetic field generating device (see Patent document 2).